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901.
902.
建议将山地学的研究对象定为以地域自然-人文综合体存在的山地系统即山地人地系统.据此提出了山地学的研究内容应围绕山地系统的性质、结构、功能及其演变理论和研究方法这一中心论题展开. 相似文献
903.
Raman spectral analysis and genetic mechanism of pseudotachylyte in Xiaoqinling detachment fault 总被引:1,自引:0,他引:1
Zhang Jinjiang Liu Shuwen Zheng Yadong Chen Jing Shi Quanzeng Yu Xiangdong Xue Liangwei 《中国科学D辑(英文版)》1998,41(3):242-247
Veins and clasts of pseudotachylyte developed in the microbreccias of the detachment fault along the boundary of the Xiaoqinling
metamorphic core complex. The Raman spectral analysis shows that there are three kinds of textures in the matrices of the
pseudotachylyte, i.e. ultracataclastic fine-grained texture, cryptocrystalline texture and both of them with minute quantity
of glass. The three different textures are the results of different degrees of ultracataclasis. This demonstrates that ultracataclasis-comminution-melting
is the genetic mechanism of the pseudotachylytes in the Xiaoqinling detachment fault and the ultracataclasis-comminution dominates
in their formation.
Project supported by the National Natural Science Foundation of China (Grant No. 49472142). 相似文献
904.
A. Yu. Aleksandrova 《Geography and Natural Resources》2016,37(1):18-25
A multifactor tourism typology of countries of the world having a structural-functional character has been developed. It provides insight into the typological features of the global spatial structure of international tourism, reflecting the intensity of international tourism flows, their geography, the importance of the tourism industry for the national economy as well as the general attributes of territorial organization of international tourism, and the dynamics of its development. Five main types of touristic types of countries have been identified. The following indicators were used for characterization of the countries and their comparison: the size of the territory, and the population size; the general level of socioeconomic development; the level and character of development of international tourism; the characteristic properties of touristic demand; the orientedness of tourism flows; characteristics of touristic offer; the degree of influence of international tourism on the national economy; characteristics of the state policy in the sphere of tourism, and touristic specialization. The first type includes the economically highly developed countries with mature national systems of international tourism forming the center of the world’s touristic space. The second type is represented by countries belonging to the semi-periphery of the world’s touristic space with an intensely forming state-supported polyfunctional system of international tourism. The third type includes moderately developed countries of the semi-periphery of the world’s touristic space with a polyfunctional system of international tourism in the stage of transformation and formation of a civilized travel market. The fourth type comprises small island states of the Caribbean Basin which belong to the semi-periphery and, in part, to the “advanced” periphery of the world’s touristic space. The fifth type combines developing countries belonging to the periphery of the world’s touristic space, with a weakly developed market of international tourism. 相似文献
905.
906.
907.
利用非组合精密单点定位(PPP)可以提取高精度的电离层延迟。测站多径误差会影响伪距和相位测量精度,影响实时PPP电离层延迟提取的精度以及收敛速度。对于静态观测站,利用对GPS卫星地面跟踪的时间重复性进行恒星日滤波可以消除多径误差的影响。通过事后处理提取前几日的码和载波相位残差序列,利用恒星日滤波建立多径误差改正模型,修正实时观测数据,可以改善实时电离层延迟估计性能。对IGS观测站的实测数据分析表明,应用恒星日滤波多径误差修正后,实时电离层延迟提取的精度由0.185 m提高到0.028 m,新进卫星的电离层参数估计收敛时间由80 min减少为35 min。 相似文献
908.
Gorokhov I. M. Kuznetsov A. B. Vasilieva I. M. Kramchaninov A. Yu. Rizvanova N. G. Konstantinova G. V. 《Doklady Earth Sciences》2021,500(1):715-719
Doklady Earth Sciences - The first direct Pb–Pb dating of carbonate rocks of the Kamo Group has been carried out. The Pb–Pb age of carbonates of the lower units (the Madra, Jurubchen,... 相似文献
909.
910.